Retrospective analysis of dual-phase MDCT and follow-up EUS/EUS-FNA in the diagnosis of pancreatic cancer

Radiologists' Expectations of Artificial Intelligence in Pancreatic Cancer Imaging: How Good Is Good Enough?

BACKGROUND

Existing (artificial intelligence [AI]) tools in radiology are modeled without necessarily considering the expectations and experience of the end user-the radiologist. The literature is scarce on the tangible parameters that AI capabilities need to meet for radiologists to consider them useful tools.

OBJECTIVE

The purpose of this study is to explore radiologists' attitudes toward AI tools in pancreatic cancer imaging and to quantitatively assess their expectations of these tools.

METHODS

A link to the survey was posted on the www.ctisus.com website, advertised in the www.ctisus.com email newsletter, and publicized on LinkedIn, Facebook, and Twitter accounts. This survey asked participants about their demographics, practice, and current attitudes toward AI. They were also asked about their expectations of what constitutes a clinically useful AI tool. The survey consisted of 17 questions, which included 9 multiple choice questions, 2 Likert scale questions, 4 binary (yes/no) questions, 1 rank order question, and 1 free text question.

RESULTS

A total of 161 respondents completed the survey, yielding a response rate of 46.3% of the total 348 clicks on the survey link. The minimum acceptable sensitivity of an AI program for the detection of pancreatic cancer chosen by most respondents was either 90% or 95% at a specificity of 95%. The minimum size of pancreatic cancer that most respondents would find an AI useful at detecting was 5 mm. Respondents preferred AI tools that demonstrated greater sensitivity over those with greater specificity. Over half of respondents anticipated incorporating AI tools into their clinical practice within the next 5 years.

CONCLUSION

Radiologists are open to the idea of integrating AI-based tools and have high expectations regarding the performance of these tools. Consideration of radiologists' input is important to contextualize expectations and optimize clinical adoption of existing and future AI tools.

Clinical application of Al18F-NOTA-FAPI PET/CT in diagnosis and TNM staging of pancreatic adenocarcinoma, compared to 18F-FDG

PURPOSE

This study aimed to investigate the ability of Al18F-NOTA-FAPI PET/CT to diagnose pancreatic carcinoma and tumor-associated inflammation with the comparison of 18F-FDG PET/CT.

METHODS

Prospective analysis of Al18F-NOTA-FAPI PET/CT and 18F-FDG PET/CT scans of 31 patients from 05/2021 to 05/2022 were analyzed. Al18F-NOTA-FAPI imaging was performed in patients who had Ce-CT and FDG PET/CT and the diagnosis was still unclear. Follow-up histopathology or radiographic examination confirmed the findings. Radiotracer uptake, diagnostic performance, and TNM (tumor-node-metastasis) classifications were compared.

RESULTS

A total of 31 patients with pancreatic carcinoma (all were adenocarcinoma) underwent Al18F-NOTA-FAPI-04 PET/CT, including 20 male and 11 female patients, with a mean age of 58.2 ± 8.5 years. FAPI-04 PET/CT imaging showed a higher value of SUVmax-15min/30min/60min, SUVmean-15min/30min/60min, TBR1, and TBR2 in pancreatic carcinoma than FDG (all P < 0.01). The mean level of Al18F-NOTA FAPI-04 uptake values of the pancreatic ductal adenocarcinoma was higher than that of pancreatitis in both SUVmax-30min (P < 0.01), SUVmean-30min (P < 0.05), SUVmax-60min (P < 0.01), and SUVmean-60min (P < 0.01). The FAPI △SUVmax-1, △SUVmax-2, and △SUVmean-2 uptake values of pancreatic carcinoma were higher than tumor-associated inflammation (all P < 0.01). TNM staging of 16/31 patients changed after Al18F-NOTA FAPI-04 PET/CT examination with all upstaging changes.

CONCLUSION

Al18F-NOTA-FAPI-04 PET/CT at 15 and 30 min also demonstrated an equivalent detection ability of pancreatic lesion to 18F-FDG PET/CT. Delayed-phase Al18F-NOTA-FAPI-04 PET/CT can help differentiate pancreatic carcinoma and tumor-associated inflammation. Al18F-NOTA FAPI-04 PET/CT also performed better than FDG PET/CT in TNM staging.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2100051406. Registered 23 September 2021, https://www.chictr.org.cn/showproj.html?proj=133033.

Annotation-Efficient Deep Learning Model for Pancreatic Cancer Diagnosis and Classification Using CT Images: A Retrospective Diagnostic Study

The aim of this study was to develop a novel deep learning (DL) model without requiring large-annotated training datasets for detecting pancreatic cancer (PC) using computed tomography (CT) images. This retrospective diagnostic study was conducted using CT images collected from 2004 and 2019 from 4287 patients diagnosed with PC. We proposed a self-supervised learning algorithm (pseudo-lesion segmentation (PS)) for PC classification, which was trained with and without PS and validated on randomly divided training and validation sets. We further performed cross-racial external validation using open-access CT images from 361 patients. For internal validation, the accuracy and sensitivity for PC classification were 94.3% (92.8-95.4%) and 92.5% (90.0-94.4%), and 95.7% (94.5-96.7%) and 99.3 (98.4-99.7%) for the convolutional neural network (CNN) and transformer-based DL models (both with PS), respectively. Implementing PS on a small-sized training dataset (randomly sampled 10%) increased accuracy by 20.5% and sensitivity by 37.0%. For external validation, the accuracy and sensitivity were 82.5% (78.3-86.1%) and 81.7% (77.3-85.4%) and 87.8% (84.0-90.8%) and 86.5% (82.3-89.8%) for the CNN and transformer-based DL models (both with PS), respectively. PS self-supervised learning can increase DL-based PC classification performance, reliability, and robustness of the model for unseen, and even small, datasets. The proposed DL model is potentially useful for PC diagnosis.

Low keV portal venous phase as a surrogate for pancreatic phase in a pancreatic protocol dual-energy CT: feasibility, image quality, and lesion conspicuity

OBJECTIVE

To assess the feasibility of a proposed pancreatic protocol CT generated from portal-venous phase (PVP) dual-energy CT (DECT) acquisition and its impact on image quality, lesion conspicuity, and arterial visualization/involvement.

METHODS

We included 111 patients (mean age, 66.8 years) who underwent pancreatic protocol DECT (pancreatic phase, PP, and PVP). The original DECT acquisition was used to create two data sets-standard protocol (50 keV PP/65 keV PVP) and proposed protocol (40 keV/65 keV PVP). Three reviewers evaluated the two data sets for image quality, lesion conspicuity, and arterial visualization/involvement using a 5-point scale. The signal-to-noise ratio (SNR) of pancreas and lesion-to-pancreas contrast-to-noise ratio (CNR) was calculated. Qualitative scores, quantitative parameters, and dose-length product (DLP) were compared between standard and proposed protocols.

RESULTS

The image quality, SNR of pancreas, and lesion-to-pancreas CNR of the standard and proposed protocol were comparable (p = 0.11-1.00). Lesion conspicuity was comparable between the standard and proposed protocols for pancreatic ductal adenocarcinoma (p = 0.55) and pancreatic cysts (p = 0.28). The visualization of larger arteries and arterial involvement were comparable between the two protocols (p = 0.056-1.00) while the scores were higher for smaller vessels in the standard protocol (p < 0.0001-0.0015). DLP of the proposed protocol (670.4 mGy·cm) showed a projected 42% reduction than the standard protocol (1145.9 mGy·cm) (p < 0.0001).

CONCLUSION

Pancreatic protocol CT generated from a single PVP DECT acquisition is feasible and could potentially be an alternative to the standard pancreatic protocol with PP and PVP.

KEY POINTS

• The lesion conspicuity for focal pancreatic lesions was comparable between the proposed protocol and standard dual-phase pancreatic protocol CT. • Qualitative and quantitative image assessments were almost comparable between two protocols. • The radiation dose of a proposed protocol showed a projected 42% reduction from the conventional protocol.

Simulated twin-phase pancreatic CT generated using single portal venous phase dual-energy CT acquisition in pancreatic ductal adenocarcinoma

PURPOSE

To evaluate the diagnostic performance of a simulated twin-phase pancreatic protocol CT generated from a single portal venous phase (PVP) dual-energy CT (DECT) acquisition in patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

In this retrospective study, we included 63 patients with PDAC who underwent pancreatic protocol (pancreatic phase [PP] and PVP) DECT. Two data sets were created from this original acquisition-(1) Standard protocol (50 keV PP/65 keV PVP) and (2) Simulated protocol (40 keV/65 keV PVP). Using a 5-point scale, three readers scored image quality, tumor conspicuity, and arterial involvement by the PDAC. Signal-to-noise ratio (SNR) of the pancreas and tumor-to-pancreas contrast-to-noise ratio (CNR) were calculated. Qualitative scores, quantitative parameters, and radiation dose were compared between standard and simulated protocols.

RESULTS

No significant difference in detection rate of PDAC was seen between the standard (58/63, 92.1%) and simulated protocols (56/63, 88.9%) (P = 0.76). Subjective scoring for arterial involvement for celiac (P = 0.86), superior mesenteric (P = 0.88), splenic (P = 0.86), common hepatic (P = 0.52), gastroduodenal (P = 0.95), first jejunal (P = 0.48) arteries, and aorta (P = 1.00) were comparable between two protocols. The image quality (P = 0.14), the SNR of the pancreas (P = 0.15), and CNR (P = 0.54) were comparable between two protocols. The projected mean dose-length product (DLP) (629.6 ± 148.3 mGy cm) in the simulated protocol showed a 44% reduction in radiation dose compared to the standard protocol (mean DLP, 1123.3 ± 268.9 mGy cm) (P < 0.0001).

CONCLUSIONS

Low keV images generated from a PVP DECT acquisition allows creation of a twin-phase pancreatic protocol CT with comparable diagnostic accuracy for detecting PDAC with significant reduction in radiation dose. Reduced radiation dose is desirable in surveillance and screening for pancreatic diseases.

A simple method for diagnosing gallbladder malignant tumors with subserosa invasion by endoscopic ultrasonography

BACKGROUND

If the depth of gallbladder malignant tumor (GBMT) invasion is deeper than the subserosa (ss), cholecystectomy is insufficient. In past reports that used endoscopic ultrasonography (EUS) to diagnose the depth of tumor invasion, it was difficult to diagnose GMBT invasion in the ss without a narrow or disrupted lateral hyperechoic layer (LHEL). Therefore, we developed a simple preoperative method to diagnose GBMTs with ss invasion.

METHODS

Forty-nine GBMT patients who underwent both EUS and surgery were enrolled: 15 patients whose tumors invaded the mucosa (m) or muscularis propria (mp) were classified as the "shallow group", and 34 patients whose tumors invaded the ss were classified as the "deep group". The EUS findings were compared between the two groups.

RESULTS

An irregular (narrow or thickened) LHEL was significantly more frequently observed on EUS in the deep group than in the shallow group. The diagnosis of ss invasion based on an irregular LHEL had the highest sensitivity and accuracy among the EUS imaging parameters (sensitivity 97.1% (33/34), specificity 86.7% (13/15), accuracy 93.8% (46/49)). When the deep group was limited to patients with a tumor depth of ss, the results were similar. When an irregular LHEL was used, the diagnostic accuracy of GBMTs with ss invasion was not significantly different between EUS specialists and beginners.

CONCLUSIONS

The observation of an irregular (thickened or narrow) LHEL observed on EUS could be a reliable and simple method of diagnosing GBMTs with ss invasion and could contribute to choosing an appropriate surgical method.

Value of endoscopic ultrasonography in the observation of the remnant pancreas after pancreatectomy

BACKGROUND

Endoscopic ultrasonography (EUS) is proven to be a more specific and sensitive method for detecting pancreatic lesions. However, usefulness of EUS after pancreatectomy has not been reported. This study aimed to evaluate the observational capability of EUS for the remnant pancreas (RP) after pancreatectomy.

PATIENT AND METHODS

This single-center, retrospective study enrolled 395 patients who underwent pancreatectomy at Onomichi General Hospital between December 2002 and March 2016, 45 patients who underwent EUS for RP were included for analysis. We evaluated the usefulness of EUS for RP using logistic regression analysis.

RESULTS

Complete observation of the RP was done in 42 patients (93%). In the initial surgical procedure, 21 patients underwent pancreaticoduodenectomy (PD), and 24 patients underwent distal pancreatectomy (DP). PD and DP were observed in 85% (18/21) and 100% (24/24) cases, respectively. A comparison of the detection capability of EUS and contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI) showed that EUS was significantly superior to contrast-enhanced CT or MRI (p < 0.01). Eight of the 45 patients showed recurrence lesions in the RP. The median recurrence period was 33 months. Predictive factors for recurrence in the univariate and multivariate analyses were significantly different in space occupying lesion with EUS findings (p < 0.01) and elevated CA19-9(p < 0.01).

CONCLUSIONS

EUS was able to observe the RP in almost all cases. In addition, the detection capability of EUS was significantly superior to those of CT or MRI. We recommend that all patients with RP should undergo EUS, and a longer follow-up must be performed.

Incidental biliary dilation in the era of the opiate epidemic: High prevalence of biliary dilation in opiate users evaluated in the Emergency Department

BACKGROUND

Biliary dilation is frequently related to obstruction; however, non-obstructive factors such as age and previous cholecystectomy have also been reported. In the past two decades there has been a dramatic increase in opiate use/dependence and utilization of cross-sectional abdominal imaging, with increased detection of biliary dilation, particularly in patients who use opiates.

AIM

To evaluate associations between opiate use, age, cholecystectomy status, ethnicity, gender, and body mass index utilizing our institution’s integrated informatics platform.

METHODS

One thousand six hundred and eighty-five patients (20% sample) presenting to our Emergency Department for all causes over a 5-year period (2011-2016) who had undergone cross-sectional abdominal imaging and had normal total bilirubin were included and analyzed.

RESULTS

Common bile duct (CBD) diameter was significantly higher in opiate users compared to non-opiate users (8.67 mm vs 7.24 mm, P < 0.001) and in patients with a history of cholecystectomy compared to those with an intact gallbladder (8.98 vs 6.72, P < 0.001). For patients with an intact gallbladder who did not use opiates (n = 432), increasing age did not predict CBD diameter (r² = 0.159, P = 0.873). Height weakly predicted CBD diameter (r² = 0.561, P = 0.018), but weight, body mass index, ethnicity and gender did not.

CONCLUSION

Opiate use and a history of cholecystectomy are associated with CBD dilation in the absence of an obstructive process. Age alone is not associated with increased CBD diameter. These findings suggest that factors such as opiate use and history of cholecystectomy may underlie the previously-reported association of advancing age with increased CBD diameter. Further prospective study is warranted.

Use of Precision Imaging in the Evaluation of Pancreas Cancer

Pancreas cancer is an aggressive and fatal disease that will become one of the leading causes of cancer mortality by 2030. An all-out effort is underway to better understand the basic biologic mechanisms of this disease ranging from early development to metastatic disease. In order to change the course of this disease, diagnostic radiology imaging may play a vital role in providing a precise, noninvasive method for early diagnosis and assessment of treatment response. Recent progress in combining medical imaging, advanced image analysis and artificial intelligence, termed radiomics, can offer an innovate approach in detecting the earliest changes of tumor development as well as a rapid method for the detection of response. In this chapter, we introduce the principles of radiomics and demonstrate how it can provide additional information into tumor biology, early detection, and response assessments advancing the goals of precision imaging to deliver the right treatment to the right person at the right time.

Utility of CT Radiomics Features in Differentiation of Pancreatic Ductal Adenocarcinoma From Normal Pancreatic Tissue

OBJECTIVE. The objective of our study was to determine the utility of radiomics features in differentiating CT cases of pancreatic ductal adenocarcinoma (PDAC) from normal pancreas. MATERIALS AND METHODS. In this retrospective case-control study, 190 patients with PDAC (97 men, 93 women; mean age ± SD, 66 ± 9 years) from 2012 to 2017 and 190 healthy potential renal donors (96 men, 94 women; mean age ± SD, 52 ± 8 years) without known pancreatic disease from 2005 to 2009 were identified from radiology and pathology databases. The 3D volume of the pancreas was manually segmented from the preoperative CT scans by four trained researchers and verified by three abdominal radiologists. Four hundred seventy-eight radiomics features were extracted to express the phenotype of the pancreas. Forty features were selected for analysis because of redundancy of computed features. The dataset was divided into 255 training cases (125 normal control cases and 130 PDAC cases) and 125 validation cases (65 normal control cases and 60 PDAC cases). A random forest classifier was used for binary classification of PDAC versus normal pancreas of control cases. Accuracy, sensitivity, and specificity were calculated. RESULTS. Mean tumor size was 4.1 ± 1.7 (SD) cm. The overall accuracy of the random forest binary classification was 99.2% (124/125), and AUC was 99.9%. All PDAC cases (60/60) were correctly classified. One case from a renal donor was misclassified as PDAC (1/65). The sensitivity was 100%, and specificity was 98.5%. CONCLUSION. Radiomics features extracted from whole pancreas can be used to differentiate between CT cases from patients with PDAC and healthy control subjects with normal pancreas.

Cinematic rendering of pancreatic neoplasms: preliminary observations and opportunities

Pancreatic cancer is the third most common cause of cancer death and CT is the most commonly used modality for the initial evaluation of suspected pancreatic cancer. Post-processing of CT data into 2D multiplanar and 3D reconstructions has been shown to improve tumor visualization and assessment of tumor resectability compared to axial slices, and is considered the standard of care. Cinematic rendering is a new 3D-rendering technique that produces photorealistic images, and it has the potential to more accurately depict anatomic detail compared to traditional 3D reconstruction techniques. The purpose of this article is to describe the potential application of CR to imaging of pancreatic neoplasms. CR has the potential to improve visualization of subtle pancreatic neoplasms, differentiation of solid and cystic pancreatic neoplasms, assessment of local tumor extension and vascular invasion, and visualization of metastatic disease.

Improving risk prediction for pancreatic cancer in symptomatic patients: a Saudi Arabian study

Background

Imaging tests used in our center are usually inadequate to confirm the high risk for pancreatic cancer. We aimed to use a combination of potential predictors including imaging tests to quantify the risk of pancreatic cancer and evaluate its utility.

Methods

This was a retrospective cohort study of patients who were suspected as having pancreatic cancer and underwent biopsy examination of pancreatic mass at King Abdulaziz Medical City, Riyadh, Saudi Arabia, between January 1, 2013, and December 31, 2016. We retrieved data on demographics, clinical history, imaging tests, and final pancreatic diagnosis from medical records.

Results

Of the 206 who underwent pancreatic biopsies, the mean age was 63.6 years; 54.4% were male. Of all the biopsies, 57.8% were malignant and 42.2% were benign masses. Nine factors contributed significantly to the risk of pancreatic cancer and were noted: older age (adjusted odds ratio [aOR] =1.048; P=0.010), male gender (aOR =4.670; P=0.008), weight loss (aOR =14.810; P=0.001), abdominal pain (aOR =7.053; P=0.0.001), blood clots (aOR =20.787; P=0.014), pancreatitis (aOR =4.473; P=0.021), jaundice (aOR =7.446; P=0.003), persistent fatigue (aOR =22.015; P=0.015), and abnormal imaging tests (aOR =67.124; P=0.001). The model yielded powerful calibration (P=0.953), excellent predictive utility (area under the receiver operating characteristic curve 96.3%; 95% CI =94.1, 98.6), with optimism-corrected area under the curve bootstrap resampling of 94.9%. An optimal cut-off risk probability of 0.513 yielded a sensitivity of 94% and specificity of 84.7% for risk classification.

Conclusion

The study developed and validated a risk model for quantifying the risk of pancreatic cancer. Nine characteristics were associated with increased risk of pancreatic cancer. This risk assessment model is feasible and highly sensitive and could be useful to improve screening performance and the decision-making process in clinical settings in Saudi Arabia.

Push vs pull method for endoscopic ultrasound-guided fine needle aspiration of pancreatic head lesions: Propensity score matching analysis

AIM

To evaluate the efficacy of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of pancreatic head cancer when pushing (push method) or pulling the echoendoscope (pull method).

METHODS

Overall, 566 pancreatic cancer patients had their first EUS-FNA between February 2001 and December 2017. Among them, 201 who underwent EUS-FNA for pancreatic head lesions were included in this study. EUS-FNA was performed by the push method in 85 patients, the pull method in 101 patients and both the push and pull methods in 15 patients. After propensity score matching (age, sex, tumor diameter, and FNA needle), 85 patients each were stratified into the push and pull groups. Patient characteristics and EUS-FNA-related factors were compared between the two groups.

RESULTS

Patient characteristics were not significantly different between the two groups. The distance to lesion was significantly longer in the push group than in the pull group (13.9 ± 4.9 mm vs 7.0 ± 4.9 mm, P < 0.01). The push method was a significant factor influencing the distance to lesion (≥ median 10 mm) (P < 0.01). Additionally, tumor diameter ≥ 25 mm (OR = 1.91, 95%CI: 1.02-3.58, P = 0.043) and the push method (OR = 1.91, 95%CI: 1.03-3.55, P = 0.04) were significant factors contributing to the histological diagnosis of malignancy.

CONCLUSION

The pull method shortened the distance between the endoscope and the lesion and facilitated EUS-FNA of pancreatic head cancer. The push method contributed to the histological diagnosis of pancreatic head cancer using EUS-FNA specimens.

Diagnosis and Detection of Pancreatic Cancer

Computed tomography is the first-line imaging modality for suspected pancreatic cancer. Magnetic resonance cholangiopancreatography is a second-line modality for suspected pancreatic cancer and is usually reserved for equivocal cases. Both computed tomography and MR are highly sensitive in the detection of pancreatic cancer, with up to 96% and 93.5% sensitivity, respectively. Computed tomography is superior to MR in the assessment of tumor resectability, with accuracy rates of up to 86.8% and 78.9%, respectively. Close attention to secondary signs of pancreatic cancer, such as pancreatic duct dilatation, abrupt pancreatic duct caliber change, and parenchymal atrophy, are critical in the diagnosis of pancreatic cancer. Emerging techniques such as radiomics and molecular imaging have the potential of identifying malignant precursors and lead to earlier disease diagnosis. The results of these promising techniques need to be validated in larger clinical studies.

PET-PANC: multicentre prospective diagnostic accuracy and health economic analysis study of the impact of combined modality 18fluorine-2-fluoro-2-deoxy-d-glucose positron emission tomography with computed tomography scanning in the diagnosis and management of pancreatic cancer

BACKGROUND

Pancreatic cancer diagnosis and staging can be difficult in 10-20% of patients. Positron emission tomography (PET)/computed tomography (CT) adds precise anatomical localisation to functional data. The use of PET/CT may add further value to the diagnosis and staging of pancreatic cancer.

OBJECTIVE

To determine the incremental diagnostic accuracy and impact of PET/CT in addition to standard diagnostic work-up in patients with suspected pancreatic cancer.

DESIGN

A multicentre prospective diagnostic accuracy and clinical value study of PET/CT in suspected pancreatic malignancy.

PARTICIPANTS

Patients with suspected pancreatic malignancy.

INTERVENTIONS

All patients to undergo PET/CT following standard diagnostic work-up.

MAIN OUTCOME MEASURES

The primary outcome was the incremental diagnostic value of PET/CT in addition to standard diagnostic work-up with multidetector computed tomography (MDCT). Secondary outcomes were (1) changes in patients' diagnosis, staging and management as a result of PET/CT; (2) changes in the costs and effectiveness of patient management as a result of PET/CT; (3) the incremental diagnostic value of PET/CT in chronic pancreatitis; (4) the identification of groups of patients who would benefit most from PET/CT; and (5) the incremental diagnostic value of PET/CT in other pancreatic tumours.

RESULTS

Between 2011 and 2013, 589 patients with suspected pancreatic cancer underwent MDCT and PET/CT, with 550 patients having complete data and in-range PET/CT. Sensitivity and specificity for the diagnosis of pancreatic cancer were 88.5% and 70.6%, respectively, for MDCT and 92.7% and 75.8%, respectively, for PET/CT. The maximum standardised uptake value (SUVmax.) for a pancreatic cancer diagnosis was 7.5. PET/CT demonstrated a significant improvement in relative sensitivity (p = 0.01) and specificity (p = 0.023) compared with MDCT. Incremental likelihood ratios demonstrated that PET/CT significantly improved diagnostic accuracy in all scenarios (p < 0.0002). PET/CT correctly changed the staging of pancreatic cancer in 56 patients (p = 0.001). PET/CT influenced management in 250 (45%) patients. PET/CT stopped resection in 58 (20%) patients who were due to have surgery. The benefit of PET/CT was limited in patients with chronic pancreatitis or other pancreatic tumours. PET/CT was associated with a gain in quality-adjusted life-years of 0.0157 (95% confidence interval -0.0101 to 0.0430). In the base-case model PET/CT was seen to dominate MDCT alone and is thus highly likely to be cost-effective for the UK NHS. PET/CT was seen to be most cost-effective for the subgroup of patients with suspected pancreatic cancer who were thought to be resectable.

CONCLUSION

PET/CT provided a significant incremental diagnostic benefit in the diagnosis of pancreatic cancer and significantly influenced the staging and management of patients. PET/CT had limited utility in chronic pancreatitis and other pancreatic tumours. PET/CT is likely to be cost-effective at current reimbursement rates for PET/CT to the UK NHS. This was not a randomised controlled trial and therefore we do not have any information from patients who would have undergone MDCT only for comparison. In addition, there were issues in estimating costs for PET/CT. Future work should evaluate the role of PET/CT in intraductal papillary mucinous neoplasm and prognosis and response to therapy in patients with pancreatic cancer.

STUDY REGISTRATION

Current Controlled Trials ISRCTN73852054 and UKCRN 8166.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Diagnostic performance of endoscopic ultrasound for detection of pancreatic malignancy following an indeterminate multidetector CT scan: a systemic review and meta-analysis

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis in part due to delayed diagnosis. Even with advances in cross-sectional imaging, small pancreatic malignancies can be missed. We sought to determine the performance of endoscopic ultrasound (EUS) in those without an obvious mass on multi-detector CT scan (MDCT), but with clinical suspicion for pancreatic malignancy.

METHODS

Multiple databases were systematically searched to identify studies that assessed the diagnostic performance of EUS after negative or inconclusive pancreatic protocol MDCT for detection of pancreatic malignancy when clinically suspected. A total of four studies met the inclusion criteria. The point estimates in each study were compared to the summary pooled estimates of sensitivity and specificity with the aid of forest plots. Funnel plots and Egger's test were employed to evaluate possible publication bias.

RESULTS

EUS-guided fine needle aspiration was performed in all studies. EUS was performed in 206 subjects with a clinical suspicion of a pancreatic mass but with an indeterminate MDCT. A pancreatic mass (mean size 21 ± 1.2 mm) was identified in 70% (n = 144) of the subjects, and 42.2% (n = 87) were diagnosed with PDAC. The pooled estimates of EUS for diagnosing pancreatic malignancy in the setting of an indeterminate MDCT were a sensitivity of 85% (95% CI 69-94%), specificity of 58% (95% CI 40-74%), positive predictive value of 77% (69-84%), negative predictive value of 66% (95% CI 53-77%), and an accuracy of 75% (95% CI 67-82). The summary area under the ROC curve was 0.80 (95% CI 0.52-0.89). The funnel plots and Egger's test did not show a significant publication bias.

CONCLUSIONS

The yield of EUS is comparatively higher for the diagnosis of a pancreatic malignancy in patients with suspected cancer, but a non-diagnostic MDCT. Importantly, the majority of the lesions missed on CT represent PDAC, in which early diagnosis is essential.

Contrast-enhanced harmonic endoscopic ultrasonography in gallbladder cancer and pancreatic cancer

Endoscopic ultrasonography (EUS) plays a major role in diagnosing gallbladder (GB) cancer and pancreatic cancer (PC). In cases of GB cancer, EUS allows for precise observations of morphology and wall layers. However, proficiency is required for the morphologic diagnosis of GB tumors. Therefore, contrast-enhanced harmonic EUS (CH-EUS) began to be performed to diagnose GB lesions. CH-EUS enables real-time observation of the hemodynamics of GB tumors. The enhanced patterns generated by CH-EUS improve precision in the diagnosis of such tumors.PC appears as a hypoechoic mass on EUS. However, distinguishing between PC and mass-forming pancreatitis or focal autoimmune pancreatitis (AIP) is difficult via conventional EUS. CH-EUS allows for differentiating among these diseases (PC is hypoenhanced and heterogeneously enhanced, pancreatitis is isoenhanced, and a pancreatic neuroendocrine tumor is hyperenhanced). EUS-guided fine needle aspiration (EUS-FNA) also contributes to pathological diagnoses of pancreatic lesions. However, certain PC patients cannot be diagnosed via EUS-FNA. PC is heterogeneously enhanced on CH-EUS, and unenhanced regions have been reported to be areas of fibrosis or necrosis. CH-EUS-guided fine needle aspiration (CH-EUS-FNA) permits puncturing of the enhanced area while avoiding necrotic and fibrotic regions. Moreover, as CH-EUS findings have been quantitatively analyzed, a time-intensity curve (TIC) has become usable for diagnosing solid pancreatic lesions. CH-EUS-related techniques have been developed and increasingly utilized in the pancreaticobiliary area.

The incremental benefit of EUS for identifying unresectable disease among adults with pancreatic adenocarcinoma: A meta-analysis

Background and study aims

It is unclear to what extent EUS influences the surgical management of patients with pancreatic adenocarcinoma. This systematic review sought to determine if EUS evaluation improves the identification of unresectable disease among adults with pancreatic adenocarcinoma.

Patients and methods

We searched MEDLINE, EMBASE, bibliographies of included articles and conference proceedings for studies reporting original data regarding surgical management and/or survival among patients with pancreatic adenocarcinoma, from inception to January 7th 2017. Our main outcome was the incremental benefit of EUS for the identification of unresectable disease (IB_EUS). The pooled IB_EUS were calculated using random effects models. Heterogeneity was explored using stratified meta-analysis and meta-regression.

Results

Among 4,903 citations identified, we included 8 cohort studies (study periods from 1992 to 2007) that examined the identification of unresectable disease (n = 795). Random effects meta-analysis suggested that EUS alone identified unresectable disease in 19% of patients (95% confidence interval [CI], 10–33%). Among those studies that considered portal or mesenteric vein invasion as potentially resectable, EUS alone was able to identify unresectable disease in 14% of patients (95% CI 8–24%) after a CT scan was performed.

Limitations

The majority of the included studies were retrospective.

Conclusions

EUS evaluation is associated with increased identification of unresectable disease among adults with pancreatic adenocarcinoma.

Imaging Tests for the Diagnosis and Staging of Pancreatic Adenocarcinoma: A Meta-Analysis

Imaging tests are central to the diagnosis and staging of pancreatic adenocarcinoma. We performed a systematic review and meta-analysis of the pertinent evidence on 5 imaging tests (computed tomography (CT), magnetic resonance imaging, CT angiography, endoscopic ultrasound with fine-needle aspiration, and combined positron emission tomography with CT). Searches of several databases up to March 1, 2014, yielded 9776 articles, and 24 provided comparative effectiveness of 2 or more imaging tests. Multiple reviewers applied study inclusion criteria, extracted data from each study, rated the risk of bias, and graded the strength of evidence. Data included accuracy of diagnosis and resectability in primary untreated pancreatic adenocarcinoma, including tumor stage, nodal stage, metastases, and vascular involvement. Where possible, study results were combined using bivariate meta-analysis. Studies were at low or moderate risk of bias. Most comparisons between imaging tests were insufficient to permit conclusions, due to imprecision or inconsistency among study results. However, moderate-grade evidence revealed that CT and magnetic resonance imaging had similar sensitivities and specificities for both diagnosis and vascular involvement. Other conclusions were based on low-grade evidence. In general, more direct evidence is needed to inform decisions about imaging tests for pancreatic adenocarcinoma.

Absence of a Periampullary Mass on Cross-sectional Imaging Delays Diagnosis and Time to Pancreatoduodenectomy But Does Not Impair Outcome

BACKGROUND

The aim of this study was to assess whether the lack of a radiological mass in patients with periampullary malignancies led to protracted diagnosis, delayed resection, and an inferior outcome.

METHODS

The departmental database was interrogated to identify all patients undergoing pancreatoduodenectomy during the period 2000-2014. The absence of a mass on cross-sectional and endoscopic ultrasound was noted. The interval between imaging and surgery was evaluated and related to the absence of a mass. The relationship between mass/no mass and the pathological profile was also assessed.

RESULTS

Among 490 patients who underwent pancreatoduodenectomy for periampullary malignancies, masses were detected in 299 patients. Patients with undetected mass on either endoscopic ultrasonography (EUS) or computed tomography (CT)/magnetic resonance imaging (MRI) had a longer median interval from initial imaging to resection than detected mass with no difference in survival (66 vs. 41 days, p = 0.001). The absence of a mass was more common in cholangiocarcinomas (p < 0.001). The absence of a mass on imaging was associated with smaller size on final histopathology (2.4 vs. 2.8 cm; p < 0.001).

CONCLUSIONS

The absence of a mass with all modalities in patients with a periampullary malignancy leads to a delayed diagnosis without a significant effect on survival.

The efficacy of contrast-enhanced harmonic endoscopic ultrasonography in diagnosing gallbladder cancer

The aim of this study was to review the efficacy of contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) in diagnosing gallbladder (GB)-protruded lesions. Thirty-eight patients underwent CH-EUS for the diagnosis of GB-protruded lesions. Twenty-four patients whose major axes of their largest lesions were longer than 10 mm were recruited. The ability of CH-EUS to diagnose malignant or benign lesions was reviewed. We treated lesions with brindled enhanced patterns as malignant and those with uniformly enhanced or unenhanced patterns as benign. Furthermore, three gastroenterologists who were not familiar with pancreaticobiliary EUS compared the diagnostic abilities of CH-EUS and conventional EUS using photographs. The sensitivity, specificity, and malignant accuracy of CH-EUS were 100, 94.4, and 95.8%, respectively. The number of lesions that presented with enhanced patterns was significantly different between the malignant lesions and the benign lesions (P < 0.001). In the comparison of diagnostic abilities between CH-EUS and conventional EUS by the three gastroenterologists, CH-EUS was significantly superior to conventional EUS in terms of sensitivity, specificity, and accuracy (76.1 vs. 42.9%, P = 0.029; 66.7 vs. 39.2%, P = 0.005; and 69.4 vs. 40.3%, P < 0.001; respectively). In conclusion, CH-EUS was useful for diagnosing malignant and benign GB-protruded lesions.

Conventional versus contrast-enhanced harmonic endoscopic ultrasonography-guided fine-needle aspiration for diagnosis of solid pancreatic lesions: A prospective randomized trial

OBJECTIVES

Contrast-enhanced harmonic endoscopic ultrasonography (CEH-EUS) has been used to diagnose solid pancreatic lesions (SPLs). The aim of this study was to investigate the efficacy of CEH-EUS-guided fine-needle aspiration (CEH-EUS-FNA) compared with that of conventional EUS-FNA for the diagnosis of SPLs.

METHODS

Forty patients with solid pancreatic lesions who visited Fukushima Medical University between September 2013 and June 2014 were recruited for this prospective study. Twenty patients underwent CEH-EUS-FNA, and 20 patients underwent conventional EUS-FNA. The sampling rate, sensitivity, accuracy, and number of needle passes required to obtain sufficient samples were compared between the two groups.

RESULTS

Patient characteristics, sampling rate, accuracy, and sensitivity were not significantly different between the two groups. The final diagnosis of patients who underwent CEH-EUS-FNA was pancreatic cancer in 19 and intraductal papillary mucinous carcinoma in one. Nineteen patients who underwent conventional EUS-FNA were finally diagnosed with pancreatic cancer and one was diagnosed as cancer of the common bile duct. There was a significant difference in the number of needle passes required. A sufficient sample was obtained on one needle pass in 60% (12/20) of CEH-EUS-FNA group compared with 25% (5/20) of the conventional EUS-FNA group.

CONCLUSIONS

Fewer needle passes were required to obtain samples from solid pancreatic lesions using CEH-EUS-FNA than those required using conventional EUS-FNA. Therefore, CEH-EUS-FNA may be more efficient and safer than conventional EUS-FNA for the diagnosis of solid pancreatic lesions.

Hybrid imaging for pancreatic malignancy: clinical applications, merits, limitations, and pitfalls

The role of PET/CT in pancreatic malignancy is evolving with new scientific evidence emerging continuously. PET/CT applications in imaging the pancreas and its organ-specific merits, limitations, and potential pitfalls are still evolving. This article provides an overview of the state-of-the-art applications of PET/CT imaging in evaluating pancreatic malignancy, comparing with conventional imaging modalities, such as contrast-enhanced CT and MRI. Current PET/MRI is also reviewed, along with brief discussion on cost-benefit analysis.

Transcriptomic and Immunohistochemical Profiling of SLC6A14 in Pancreatic Ductal Adenocarcinoma

We used a target-centric strategy to identify transporter proteins upregulated in pancreatic ductal adenocarcinoma (PDAC) as potential targets for a functional imaging probe to complement existing anatomical imaging approaches. We performed transcriptomic profiling (microarray and RNASeq) on histologically confirmed primary PDAC tumors and normal pancreas tissue from 33 patients, including five patients whose tumors were not visible on computed tomography. Target expression was confirmed with immunohistochemistry on tissue microarrays from 94 PDAC patients. The best imaging target identified was SLC6A14 (a neutral and basic amino acid transporter). SLC6A14 was overexpressed at the transcriptional level in all patients and expressed at the protein level in 95% of PDAC tumors. Very little is known about the role of SLC6A14 in PDAC and our results demonstrate that this target merits further investigation as a candidate transporter for functional imaging of PDAC.

Pancreatic head cancer in patients with chronic pancreatitis

BACKGROUND

Chronic pancreatitis (CP) is a risk factor of pancreatic adenocarcinoma (PA). The discovery of a pancreatic head lesion in CP frequently leads to a pancreaticoduodenectomy (PD) which preceded by a multidisciplinary meeting (MM). The aim of this study was to evaluate the relevance between this indication of PD and the definitive pathological results.

METHODS

Between 2000 and 2010, all patients with CP who underwent PD for suspicion of PA without any histological proof were retrospectively analyzed. The operative decision has always been made at an MM. The definitive pathological finding was retrospectively confronted with the decision made at an MM, and patients were classified in two groups according to this concordance (group 1) or not (group 2). Clinical and biological parameters were analyzed, preoperative imaging were reread, and confronted to pathological findings in order to identify predictive factors of malignant degeneration.

RESULTS

During the study period, five of 18 (group 1) patients with CP had PD were histologically confirmed to have PA, and the other 13 (group 2) did not have PA. The median age was 52.5+/-8.2 years (gender ratio 3.5). The main symptoms were pain (94.4%) and weight loss (72.2%). There was no patient's death. Six (33.3%) patients had a major complication (Clavien-Dindo classification ≥ 3). There was no statistical difference in clinical and biological parameters between the two groups. The rereading of imaging data could not detect efficiently all patients with PA.

CONCLUSIONS

Our results confirmed the difficulty in detecting malignant transformation in patients with CP before surgery and therefore an elevated rate of unnecessary PD was found. A uniform imaging protocol is necessary to avoid PD as a less invasive treatment could be proposed.

Patients with obstructive jaundice and biliary stricture ± mass lesion on imaging: prevalence of malignancy and potential role of EUS-FNA

BACKGROUND

In patients with obstructive jaundice and biliary stricture, the role of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is debated for fear of missing a potentially resectable pancreatobiliary malignancy (PBM). We evaluated the prevalence of (1) PBM; (2) lesions that do not require a potentially curative cancer surgery; and (3) potentially resectable PBMs in patients with false-negative diagnosis by EUS-FNA.

PATIENTS AND METHODS

This is a retrospective analysis of 342 patients who underwent EUS/EUS-FNA from 2002 to 2009 after presenting with obstructive jaundice and a biliary stricture. Of these, 170 patients had no definitive mass on computed tomography and 172 patients had definitive mass on computed tomography without evidence of unresectability. Final diagnosis was based on surgical pathology or definitive cytology and clinical follow-up of ≥ 12 months.

RESULTS

The mean age of patients (176 male) was 68.0±12.5 years. A final diagnosis of malignancy was made in only 248 patients (72.5%; 95% confidence interval, 67.7, 77.2). The overall accuracy of EUS-FNA for diagnosing malignancy was 92.4% (89.0, 94.8), with 91.5% sensitivity (87.1, 94.5) and 80.9% negative predictive value (72.0, 87.5). Among 21 patients with false-negative diagnosis, 8 had cholangiocarcinoma (2 resectable), 13 had pancreatic cancer (5 resectable). EUS-FNA provided information to potentially modify surgical management in 116 patients (33.9%; 95% confidence interval, 29.1, 39.0): 89 patients diagnosed as true negatives, 24 with distant malignant lymphadenopathy, and 3 with malignant lymphoma.

CONCLUSIONS

In above-defined patient subset, the risk of missing resectable tumors by EUS-FNA has been exaggerated because of artifactually low negative predictive value resulting from a high pretest probability of PBM. The actual miss rate for resectable PBM by EUS-FNA is rather small and was 2% in present cohort. Information from EUS-FNA can potentially modify surgical management in up to one third of patients.

Use of EUS-FNA in diagnosing pancreatic neoplasm without a definitive mass on CT

BACKGROUND

Diagnosis of pancreatic neoplasm is challenging in patients with inconclusive findings on pancreatic multidetector row CT (MDCT).

OBJECTIVE

To determine the diagnostic accuracy and to identify predictors of pancreatic neoplasm by EUS with FNA in this setting.

DESIGN

Retrospective chart review during the study period of January 2002 to December 2010.

SETTING

Tertiary referral center.

PATIENTS

Of the 1046 patients who underwent pancreatic EUS, 116 patients were selected because their clinical presentation was suspicious for pancreatic malignancy, but their MDCT findings were inconclusive.

INTERVENTION

EUS with FNA.

MAIN OUTCOME MEASUREMENTS

Diagnostic yield of malignancy and significance of clinical variables.

RESULTS

When surgical pathology or subsequent clinical course was used as the criterion standard, EUS with FNA had a sensitivity, specificity, positive predictive value, and accuracy of 87.3%, 98.3%, 98.5%, and 92.1%, respectively, in diagnosing a pancreatic neoplasm that was indeterminate on MDCT. Factors significantly associated with EUS detection of pancreatic ductal adenocarcinoma were total bilirubin level greater than 2 mg/dL (P < .001), CT finding of pancreatic duct dilation (P < .001), bile duct stricture (P < .001), and tumor size 1.5 cm or larger detected by EUS (P = .004). Among them, pancreatic duct dilation on CT (odds ratio 4.10; 95% confidence interval, 1.52-11.05), and tumor size 1.5 cm or larger detected by EUS (odds ratio 8.46; 95% confidence interval, 2.02-35.45) were independent risk factors.

LIMITATIONS

Retrospective design and patient referral bias.

CONCLUSIONS

When MDCT is indeterminate, EUS is a highly sensitive and accurate modality for the detection of pancreatic neoplasm, especially when the tumor is smaller than 2.0 cm.

Imaging of pancreatic ductal adenocarcinoma: State of the art

Significant advances in imaging technology have changed the management of pancreatic cancer. In computed tomography (CT), this has included development of multidetector row, rapid, thin-section imaging that has also facilitated the advent of advanced reconstructions, which in turn has offered new perspectives from which to evaluate this disease. In magnetic resonance imaging, advances including higher field strengths, thin-section volumetric acquisitions, diffusion weighted imaging, and liver specific contrast agents have also resulted in new tools for diagnosis and staging. Endoscopic ultrasound has resulted in the ability to provide high-resolution imaging rivaling intraoperative ultrasound, along with the ability to biopsy via real time imaging suspected pancreatic lesions. Positron emission tomography with CT, while still evolving in its role, provides whole body staging as well as the unique imaging characteristic of metabolic activity to aid disease management. This article will review these modalities in the diagnosis and staging of pancreatic cancer.

Imaging of pancreatic ductal adenocarcinoma: State of the art

Significant advances in imaging technology have changed the management of pancreatic cancer. In computed tomography (CT), this has included development of multidetector row, rapid, thin-section imaging that has also facilitated the advent of advanced reconstructions, which in turn has offered new perspectives from which to evaluate this disease. In magnetic resonance imaging, advances including higher field strengths, thin-section volumetric acquisitions, diffusion weighted imaging, and liver specific contrast agents have also resulted in new tools for diagnosis and staging. Endoscopic ultrasound has resulted in the ability to provide high-resolution imaging rivaling intraoperative ultrasound, along with the ability to biopsy via real time imaging suspected pancreatic lesions. Positron emission tomography with CT, while still evolving in its role, provides whole body staging as well as the unique imaging characteristic of metabolic activity to aid disease management. This article will review these modalities in the diagnosis and staging of pancreatic cancer.

State-of-the-art PET/CT of the pancreas: current role and emerging indications

Fused positron emission tomography (PET)/computed tomography (CT) is a recently developed technology that couples the functional information of PET with the anatomic details of CT. Integrated PET/CT scanners produce both PET and contrast material-enhanced CT images of the entire body in one setting. Typically, the amount of fluorine 18 (18F) fluorodeoxyglucose (FDG) uptake in normal pancreatic parenchyma is insignificant compared with that of the liver. However, both malignant (eg, adenocarcinoma) and benign (eg, acute pancreatitis) pancreatic conditions may demonstrate intense FDG uptake. PET/CT provides an opportunity to depict pancreatic tumors and distant metastases, perform preoperative staging, and monitor response to treatment, and it has proved useful in distinguishing postoperative fibrosis from recurrence. In selected cases, PET/CT findings may be used to help diagnose autoimmune pancreatitis mimicking a mass by depicting systemic involvement. PET/CT may also be used to direct biopsy to sites more likely to yield representative tumor tissue. Novel radiolabeled molecules, such as sigma-receptor ligands and 18F-3'-fluoro-3'-deoxy-l-thymidine (FLT), may play an even greater role in distinguishing tumor recurrence from postoperative fibrosis or inflammation.

Imaging of pancreatic adenocarcinoma: update on staging/resectability

Because of the evolution of treatment strategies staging criteria for pancreatic cancer now emphasize arterial involvement for determining unresectable disease. Preoperative therapy may improve the likelihood of margin negative resections of borderline resectable tumors. Cross-sectional imaging is crucial for correctly staging patients. Magnetic resonance (MR) imaging and computed tomography (CT) are probably comparable, with MR imaging probably offering an advantage for identifying liver metastases. Positron emission tomography/CT and endoscopic ultrasound may be helpful for problem solving. Clear and concise reporting of imaging findings is important. Several national organizations are developing templates to standardize the reporting of imaging findings.

Imaging in staging and management of pancreatic ductal adenocarcinoma

Pancreatic cancer is a relatively common malignancy of the gastrointestinal tract for which complete surgical excision remains the only curative option. Being infiltrative in nature and bearing a complex anatomical relationship with various organs, peritoneal ligaments and vascular structures, accurate anatomical staging is key in treatment of these patients. In this article, we will discuss and provide a brief overview of anatomy and use of imaging in staging pancreatic cancer.

Complementary roles of CT and endoscopic ultrasound in evaluating a pancreatic mass

OBJECTIVE

The objectives of our study were to illustrate normal pancreatic anatomy using endoscopic ultrasound and to show the imaging findings of solid pancreatic masses on endoscopic ultrasound and CT.

CONCLUSION

CT and endoscopic ultrasound have complementary roles in the diagnosis of solid pancreatic masses.

TrkBT1 induces liver metastasis of pancreatic cancer cells by sequestering Rho GDP dissociation inhibitor and promoting RhoA activation

Many genetic and molecular alterations, such as K-ras mutation and NF-kappaB activation, have been identified in pancreatic cancer. However, the mechanisms by which pancreatic cancer metastasizes still remain to be determined. Although we previously showed that the tropomyosin-related kinase B (TrkB) was significantly correlated with the development of liver metastasis, its function in pancreatic cancer metastasis remained unresolved. In the present study, we showed that overexpressed TrkB is an alternatively spliced transcript variant of TrkB (TrkBT1) with a unique COOH-terminal 12-amino acid sequence and is mainly localized in the cytoplasm. Our results showed that overexpression of Flag-tagged TrkBT1 but not a Flag-tagged TrkBT1 COOH-terminal deletion mutant (Flag-TrkBT1DeltaC) in nonmetastatic pancreatic cancer cells enhanced cell proliferation, promoted formation of colonies in soft agar, stimulated tumor cell invasion, and induced liver metastasis in an orthotopic xenograft mouse model of pancreatic cancer. TrkBT1 interacted with Rho GDP dissociation inhibitor (GDI) in vivo, but Flag-TrkBT1DeltaC did not. Furthermore, overexpression of Flag-TrkBT1 and knockdown of RhoGDI expression by RhoGDI short hairpin RNAs promoted RhoA activation, but Flag-TrkBT1DeltaC overexpression did not. Therefore, our results showed that TrkBT1 overexpression induces liver metastasis of pancreatic cancer and uncovered a unique signaling mechanism by which TrkBT1 sequesters GDI and activates RhoA signaling.

Role of endoscopic ultrasound in pancreatic cancer

Pancreatic cancer (PC) is the fourth most common cause of cancer deaths in Western societies. It is an aggressive tumor with an overall 5-year survival rate of less than 5%. Surgical resection offers the only possibility of cure and long-term survival for patients suffering from PC; however, unfortunately, fewer than 20% of patients suffering from PC have disease that is amendable to surgical resection. Therefore, it is important to accurately diagnose and stage these patients to enable optimal treatment of their disease. The imaging modalities involved in the diagnosis and staging of PC include multidetector CT scanning, endoscopic ultrasound (EUS), endoscopic retrograde cholangiopancreaticography and MRI. The roles and relative importance of these imaging modalities have changed over the last few decades and continue to change owing to the rapid technological advances in medical imaging, but these investigations continue to be complementary. EUS was first introduced in the mid-1980s in Japan and Germany and has quickly gained acceptance. Its widespread use in the last decade has revolutionized the management of pancreatic disease as it simultaneously provides primary diagnostic and staging information, as well as enabling tissue biopsy. This article discusses the potential benefits and drawbacks of EUS in the primary diagnosis, staging and assessment of resectability, and EUS-guided fine-needle aspiration in PC. Difficult diagnostic scenarios and pitfalls are also discussed. A suggested management algorithm for patients with suspected PC is also presented.

PEGylated gold nanoparticles conjugated to monoclonal F19 antibodies as targeted labeling agents for human pancreatic carcinoma tissue

In this study, we describe optical detection of antibody-conjugated nanoparticles bound to surgically resected human pancreatic cancer tissue. Gold nanoparticles stabilized by heterobifunctional polyethylene glycol (PEG) were prepared using approximately 15 nm spherical gold cores and covalently coupled to F19 monoclonal antibodies. The heterobifunctional PEG ligands contain a dithiol group for stable anchoring onto the gold surface and a terminal carboxy group for coupling of antibodies to the outside of the PEG shell. The nanoparticle-antibody bioconjugates form highly stable dispersions and exhibit long-term resistance to agglomeration. This has been demonstrated by dynamic light scattering, size exclusion chromatography, and transmission electron microscopy. The nanoparticle bioconjugates were used to label tumor stroma in approximately 5 mum thick sections of resected human pancreatic adenocarcinoma. After rinsing away nonbound nanoparticles and fixation, the tissue samples were imaged by darkfield microscopy near the nanoparticle resonance scattering maximum (approximately 560 nm). The images display pronounced tissue features and suggest that this novel labeling method could provide for facile identification of cancer tissue. Tumor samples treated with gold nanoparticles conjugated to nonspecific control antibodies and noncancerous pancreatic tissue treated with mAb-F19-conjugated gold nanoparticles both exhibited correctly negative results and showed no tissue staining.

Improving outcomes for operable pancreatic cancer: is access to safer surgery the problem?

Despite advances in the understanding and treatment of pancreatic cancer in the last two decades, there is a persisting nihilistic attitude among clinicians. An alarmingly high rate of under-utilization of surgical management for operable pancreatic cancer was recently reported in the USA, where more than half of patients with stage 1 operable disease and no other contraindications were not offered surgery as therapy, denying this group of patients a 20% chance of long-term survival. These data indicate that a nihilistic attitude among clinicians may be a significant and reversible cause of the persisting high mortality of patients with pancreatic cancer. This article examines the modern management of pancreatic cancer, in particular, the advances in surgical care that have reduced the mortality of pancreatectomy to almost that of colonic resection, and outlines a strategy for improving outcomes for patients with pancreatic cancer now and in the future.

Quantitative preoperative assessment of vascular involvement in pancreatic carcinoma by multi-detector row computer tomography

AIM: To evaluate the clinical efficacy of multi-detector row computer tomography (MDCT) in the preoperative quantitative assessment of vascular involvement of pancreatic carcinoma.

METHODS: MDCT was performed on 42 pancreatic carcinoma patients; the celiac trunk and portal vein were reconstructed and their branches to three-dimension vessel were analyzed by volume rendering (VR) technique, multiplanar volume reconstruction (MPVR) and maximum intensity projection (MIP) technique. Combining the source images, the scope and extent of the vessel invaded in the portal vein celiac trunk, and inferior vena cava and their branches were evaluated and measured. Compared the CT scans results with operations and pathological sections, the diagnosis value of MDCT for pancreatic carcinoma was evaluated.

RESULTS: In the 42 pancreatic carcinoma patients with operation, 252 vessels were evaluated, 77 of which were invaded by carcinoma. Celiac trunks were invaded in 12 patients, and the sensitivity and specificity were 84.6% and 96.6%, respectively. Superior mesenteric arteries were invaded in 13 patients, and the sensitivity and specificity were 100% and 96.7%, respectively. Hepatic arteries were invaded in 9 patients, and the sensitivity and specificity were 81.2% and 100%, respectively. Portal veins were invaded in 16 patients, and the sensitivity and specificity were 93.3% and 92.6%, respectively. Inferior vena cava was invaded in 6 patients, and the sensitivity and specificity were 93.3% and 92.6%, respectively. Superior mesenteric veins were invaded in 21 patients, and the sensitivity and specificity were 90% and 86.7%, respectively. In the aspect of thrombosis, MDCT scan results were consistent with the surgical findings. Only one vessel of superior mesenteric artery and vein was not correctly measured in length by MDCT. When the length between invaded vessel and vessel branches was measured, only one patient's MDCT result was consistent with the surgical result on superior mesenteric artery.

CONCLUSION: MDCT can delineate the vascular involvement of pancreatic carcinoma with high accuracy, measure the invaded vessel correctly and provide valuable information for the preoperative assessment of pancreatic carcinoma.